The title for best grid-tie solar inverter has never been closer as many of the top manufacturers release advanced new models with clever online monitoring and smart home control features. The hype around home battery systems or hybrid systems is also growing, but it is early days for batteries and the majority of solar installations still require a dedicated solar inverter. Even the much anticipated Tesla Powerwall 2 with its inbuilt inverter requires an additional solar inverter to work with a solar array.
Solar Inverter function & problems
The solar inverter is the most sophisticated part of any grid-tie solar system and unfortunately it's also the part most likely to have issues. This is not surprising considering inverters are usually located outside in harsh weather conditions including rain, humidity and extreme heat, all while generating thousands of watts of power for up to 10 hours a day. This is why it's important to use a quality inverter and mount it in a sheltered location if possible.
Due to extreme variations in humidity and temperature it is likely that many inverters mounted outdoors will experience a fault at some point during their lifetime. However the life of a solar inverter can be significantly increased by locating it inside a garage, under a carport and out of direct sunlight.
Solar panels can also develop problems over time which can result in poor performance, but unlike a faulty inverter this will generally not result in complete system shutdown. With this in mind it is worth while paying the additional cost for a reputable manufacturer (one which has been in good business standing for 5+ years and with extended warranties if available.)
Warranty and Service
Fronius, SMA and SolarEdge have ranked on top of the list for many years due to the low failure rates and great service as they usually ship replacement units in 3-5 business days. Fronius and SMA are available with 10 year warranties while SolarEdge offer a leading 12 year manufacturers warranty. Many of the lesser known 'value' brands will only repair a faulty unit if it is shipped to them (at the owner costs) and returned which often takes weeks and sometimes months. This will have a much greater financial impact due to system downtime.
Solar Inverter Types
String Solar Inverters
This review is focused on 'string' solar inverters which use a string of solar panels linked together in series. String inverters are the most common type of inverter used in Australia, Asia and Europe.
The new generation all-in-one hybrid inverters combine a solar and battery inverter together in one unit. These are becoming much more competitive against solar inverters as batteries become cheaper and more appealing. See our detailed hybrid/off-grid inverter review here
Off-grid or stand-alone power systems require powerful battery inverters with inbuilt chargers that can be setup as either AC or DC coupled systems. The modern flexible off-grid inverters sometimes known an interactive inverters are commonly used to create advanced hybrid grid-tie systems.
Micro Inverters are very small solar inverters attached directly to individual solar panels. Since each micro inverter and panel can operate independently they are a great option for complex roof layouts and locations with shading issues. Micro's are very popular, especially in north America and although they can be more expensive they do have several advantages over string inverters. Learn more about micro inverters here.
Inverter Rating Criteria
The following criteria was used to determine the best solar string inverters available on the market together with continuous feedback from solar installers and industry specialists. Note this comparison is focused on the common grid-tie solar 'string' inverters (single phase) although the larger commercial 3-phase inverters from the same manufacturers are equally well regarded.
Quality & Reliability
Service & Support
There is a considerable price difference between the hundreds of different solar inverters available. For example a low-end 5kW inverter can start from as low as $850, while a premium quality 5kW inverter with 10+ year warranty may cost $1800 or higher. However considering the high failure rates of many low-end/cheap inverters and difficulty claiming warranties we highly recommended you invest in a higher end unit. As a common saying in the solar industry goes 'the cheapest product will cost you more in the long run'.
Best Residential Solar Inverters 2018
1. Fronius - Primo and Galvo
2. SolarEdge - SE and HD wave
3. SMA - Sunny boy
4. Sungrow - SG-KLT
5. Solax Power - X1
Best Commercial Inverters (3 phase)
1. Fronius - Symo and Eco
2. SMA - Sunny Tripower & Core 1
3. SolarEdge - SE 3-phase
4. ABB - Trio, PRO and PVS
Have your say - Solar professionals feedback
In addition to continuous feedback from our solar specialists the clean energy reviews team invite all solar industry professionals and installers to provide feedback (positive or negative) from experience with any inverters (string, micro, off-grid & hybrid). Click link below.
top 5 Solar inverters - Residential
Here are we describe the top 5 residential solar inverters for 2018 based on quality, features, monitoring, warranty and service, together with feedback solar installers and industry professionals around Australia.
Fronius Inverters have surged in popularity since the release of the snap-in design around 4 years ago. The high-end Austrian manufactured inverter range has definitely become the inverter of choice for many domestic and commercial solar installations. Although customers are also raving about the performance and monitoring features, plus the reliable customer service from Fronius in Australia. Although the high demand for these premium inverters has resulted in some supply issues and quality problems were recently raised possibly due to rushed testing/inspections during manufacture. Although any issues have been promptly corrected, and with the 10 year extented warranty period the Fronius range is now generally considered the industry leader.
One of the clever features is the integrated solar DC isolator which means an external isolator box is not required, resulting in a much neater installation. Also the unique snap-in design makes servicing and installation very simple.
Wifi monitoring comes standard with all inverters via the Fronius Solar.Web. The addition of a separate Fronius Smart meter enables monitoring of energy generation and consumption and can be used as a complete home energy monitoring system. A free solarweb smart phone app is also available for android of iOS.
Full Inverter specifications here
See the detailed review of the Fronius Inverters from MC Electrical.
SolarEdge inverters have becoming increasingly popular in Australia and around the world over the last few years due to the unique design using DC optimisers which enable individual panel level monitoring and control - more information below.
See the complete detailed SolarEdge review here
The recently released HD wave (SE-H series) is one of the smallest and lightest inverters on the market and according to the specifications is also the most efficient at 99% for the larger 5 - 6KW models. This new generation inverter uses advanced thin-film capacitors and digital processors to produce a clean AC output with very low losses. All Solaredge inverters must be installed in combination with the DC optimisers (see below) which perform part of the job of a common string inverter so this is perhaps the reason Solaredge was able to package such a small efficient inverter.
The biggest advantage SolarEdge has over the competition is panel level monitoring and power optimisation through the use of panel mounted DC optimisers.
DC Optimisers are small electronic modules attached to the back of the solar panels which allow for individual panel level monitoring and power optimisation. Previously individual panel monitoring was only obtained through the use of micro-inverters, plus some add-on optimisers such those from Tigo Energy. The unique Solaredge Optimisers enable longer strings of panels (up to 22 modules) and increased safety in addition to reducing the detrimental effects of shading and panel faults, plus provide early detection of potential issues. However they can add to the complexity of the system and being an electronic device mounted on the roof may have the potential to cause issues in the longer term.
Panel shading a problem? For complex roof profiles or installations with shading issues this would be the inverter of choice.
SolarEdge also has an industry leading 12 year warranty period.
SolarEdge inverters have 'optional' wifi which together with the optimisers can provide power output data for each panel individually. This is great for both system monitoring and a very good tool for fault detection, especially for installers. Also SolarEdge definitely have one of the best smart phone apps for remote system monitoring.
See full Inverter specification here
German inverter manufacturer SMA Solar Technologies recently transferred some manufacturing from the US and South Africa to China, although they retained the head manufacturing plant in Germany. SMA inverters have a proven track record for reliability and are generally considered one of the highest quality inverters available, however this decision to move manufacturing to China has led to some doubts about the ongoing quality. Manufacturing a product in China is not always to the detriment of quality as long as the correct testing and quality control measures are implemented. It's early days but this move has already effected SMA's reputation to some degree, although some argue this will enable SMA to produce the new generation AV sunny boy inverters at a more competitive price while still maintaining the level of quality expected.
Despite the manufacturing location, local service and support is very reliable and SMA provides an optional extended 10 year warranty.
Unlike the well regarded Sunny boy TL inverters the latest AV inverter series from SMA does not have a display panel and relies solely on wifi communication, which is also a move taken by several other inverter brands. A digital display in an outdoor environment can be problematic so this may reduce faults and warranty issues in the long term, but only if the communications is very reliable and stable. Without a wifi signal and no display could make things difficult to troubleshoot if a problem does occur.
SMA have one of the best free monitoring software packages available known as the Sunny portal. Since the new Sunny boy inverters have no display for setup and monitoring, reliable communications will be vital to the success of the new models. Most SMA inverters have the wifi webconnect capability as standard and with the additional Sunny home manager 2.0 (energy meter) a complete easy to use home energy monitoring system can be created. Note the sunny portal mobile app (android) was not great with no real time data available so SMA have some work to do here.
See full Inverter specification here
Founded back in 1997 by a university professor Sungrow is one of the largest suppliers of solar inverters globally and the leading Chinese inverter manufacturer. The residential SG-KTL Sungrow inverters have become very popular among Australian installers due to the competitive price and great reliability record, plus Sungrow is a very large player internationally and has a good reputation for service and quality compared to most Chinese inverter manufacturers. Sungrow offer very good support from the Sydney based office in Australia which has further helped improve their reputation.
In additon to the well regarded SG-KTL range of solar inverters Sungrow also manufacture one of the best value hybrid solar inverters on the market - the SHK5+ ESS model which is known as a reliable and affordable inverter for home battery systems and now comes with an optional back-up device for protection during a blackout.
Sungrow inverters include Wifi monitoring as standard on all residential models using the online monitoring portal SolarInfo Bank which looks a little outdated. The smart phone App however looks much more modern.
5. Solax Power
Solax Power is a relatively new inverter manufacturer which was largely unkown in the industry until they launched the economical battery X-hybrid inverter. Solax is a subsiduary of the the much larger Suntellite Group in China which manufactures solar cells, panels and inverters with a strong emphasis on research and development. This is possibly why they have been able to produce high quality inverters with advanced features compared to many other Chinese manufacturers. Solax Power also has a strong global presence with an Australian support office located in Melbourne. The current X1 range of solar inverters do not have the sleek designs of the european rivals but at close to half the price you wouldn't expect them to compete on this level, their slogan sums them up nicely 'simple, reliable, efficient'.
One of the clever inverter options from SolaX is the very affordable X-hybrid unit which is one of the most economical battery ready solar inverters available. Due to the low pricing the new range of Solax power inverters soon to be released may put some pricing pressure on the premium inverters brands above.
Solax is also one of the few inverter manufacturers to produce large 3-phase hybrid battery inverters for larger residential and commercial applications.
The Solax online monitoring portal V2 is quite impressive and offers access via smart phone apps or web interface with battery management features for hybrid systems and email reporting, although the wifi dongle is an optional extra.
See full Inverter specification here
New for 2018
Huawei Fusion Inverters
The big mover in 2018 is from the Chinese electronics giant Huawei which is well known for their smart phones and electronic devices but little known in the Australian solar industry until now. Huawei are currently the largest producer of solar inverters globally with a wide range of large scale inverters and have invested billions into research and development over the last decade.
The first residential solar inverter from Huawei is the SUN2000L which is available in a range of sizes from 2 to 5kW. Impressively it also functions as a hybrid inverter and is extremely compact and lightweight coming it at 10.6kg. The inverter is in some ways similar to the SolarEdge HD wave inverter which uses optimisers for individual panel optimisation much like micro inverters. However unlike the HD wave the SUN2000L can function with or without optimisers. As a hybrid system the Huawei inverter uses a built in 'high voltage' DC coupling battery interface which is compatible with the popular LG chem RESUH batteries. However there is no back-up power supply function available yet but we are told it is in development.
For a detailed technical review see this breakdown from MC Electrical
With all the advanced features it will be very interesting to see how this inverter performs against the premium manufacturers in 2018.
See full specifications of the Huawei SUN2000L inverter series here
Solar Inverters - Runners up
Although this article is focused mostly on the most popular inverters , it is worth highlighting some of the other well known and trusted inverter manufacturers. Several of these brands are very reliable but only let down by the lack of service and support when an issue occurs. The most reliable of these noted by our specialists are Ingeteam and Goodwe.
ABB is a premium manufacturer but many installers we interviewed consider the old PVI range to be very outdated and have had an increasing number of failures from the older 'Aurora' branded inverters. ABB acquired Aurora 'Power-one' back in 2013 and thus have to deal with any warranty claims and service issues from the older Aurora inverters.
Our specialists have highlighted slow and substandard customer service compared to other manufacturers even though ABB is a well respected industrial giant. ABB's reputation now lies on success of the recently released range of UNO-TL and UNO-TL-DM-PLUS single phase solar inverters. However the success of the new UNO range might really depend upon the service and support from any faults or warranty claims in the future.
The new UNO inverters have the common plug & play interfaces, are lighter, more compact and offer a unique backup AC supply in case of a blackout (TBA). It is not yet known how this works without a battery but it may be a very clever innovation.
ABB are not well known for their monitoring capabilities but have recently released a new Wifi logger card (VSN300) which can be installed on all UNO and TRIO (3-phase) inverters. The new UNO-DM-PLUS inverter range has wifi as standard and offers some advanced features for smart home and smart grid applications (zero feed-in). Hopefully they include the wifi logger on all models in future.
Ingeteam is a well known, premium European inverter manufacturer which is new to the competitive small scale Australian solar market, despite being a large multinational company and having a long history in manufacturing power conversion equipment. The company of Spanish origin has advanced R&D capabilities and currently manufacturer a wide range of quality solar and hybrid inverters for the residential and commercial markets, in addition to much larger utility scale central solar inverters.
The residential (2.5 - 6kW) 1Play TL-M series dual MPPT solar inverters appear to be very well engineered with many advanced features and monitoring, however as yet none of our Australian specialists have had any direct experience. Looking forward to seeing more and reviewing the Ingeteam inverters during 2018.
GoodWe is a large, well known Chinese inverter manufacturer established in 2010. Goodwe like most Chinese brands have a mixed reputation in Australia due to some previous quality issues, but have improved considerably over the last few years. The Goodwe hybrid inverter ( GW5048D-ES) is a standout product from the Goodwe range and is well regarded in the industry with many other manufacturers incoporating this inverter into there own home battery energy storage systems (ESS). All Goodwe inverters include Wifi monitoring as standard.
Delta is generally well regarded by installers as one of better value Chinese made inverters. This is not surpising as Delta Group is a gloabal electronics giant which has been manufacturing power control systems around the world since 1971. Although the new RPI range released a few years back does not seem to have become a huge hit with installers, possibly due to the the tough competition from the many other lower cost inverters manufacturers. With a 10 year product warranty as standard and an Australian office located in Melbourne, it is still one of the more trusted value level inverters available.
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